More on Mouse Sperm

More on Mouse Sperm

There’s a headline guaranteed to draw a crowd. But truly, the stories that have run since I blogged off yesterday are all either about the Wisconsin patent issue or the German research on mouse testicles. I think I’ve probably said all there is to say about the patent issue, so it’s full speed ahead on the research. Yesterday I only had a very short UPI story to work with, today there are many more. Let’s start with the Washington Post (I have a partiality for Post articles because Rick Weiss, who covers the subject, seems very knowledgeable and writes well).

The researchers isolated cells known as “spermatogonial stem cells” from the mouse testicles. They are not sperm themselves, but are the cells that differentiate into sperm cells. The researchers found that the cells can make “countless” copies of themselves (as they would need to, to ensure a lifetime supply of sperm), and can be coaxed to grow into any kind of body cell. They have already been grown into liver, muscle, pancreas, and heart cells, as well as the neural cell that secrete dopamine (lack thereof is the cause of Parkinson’s). The article reports that the heart cells coalesced in culture and began beating. (How cool is that?!) Other scientists who were quoted in the article thought the research looked promising but of course not conclusive yet—these are mice, not men. The article also reported that the journal Nature required many additional documents and tests before accepting the article for publication.

One concern raised in the Post article was by another scientist who thought it possible that the sperm producing cells might have “molecular imprints” that make producing normal other tissue problematic.

The BBC reports that the cells were grown into colonies similar to embryonic stem cells and are known as multipotent adult germline stem cells (maGSCs). They are also able to differentiate into the three basic tissue layers of an embryo. One British scientist, who called the paper “intriguing,” said that mice cell proliferate much more readily than human cells, and that they also require different compounds to grow.

The Boston Globe also had a fairly extensive article, and quoted Bishop Tadeusz Pacholczyk, director of education for the National Catholic Bioethics Center in Philadelphia, as saying it was a step in the right direction. The Globe article gives some background on cloning and also reports that the German team had improvements in the method of purifying the stem cells (itself a noteworthy advance, I expect) and the discovery of a medium that allowed the differentiation.

Both the Post and the Globe report that the procedure for extracting these cells from human testicles could be done easily, in the same manner as a biopsy done for fertility studies.

An AP story printed in the Houston Chronicle (among other papers, of course) reports on the study but does not say more than the Post. Reuters also has a story presenting the same information.

My thoughts:

Exciting. But our goal is not to cure mouse health problems. Let’s see if this works with human sperm-producing cells. I’d like to propose that all male opponents of embryonic stem cell research, beginning with President Bush, donate their own cells for research.

If the cells can be grown and differentiated as the mice cells could, are there risks of cancer developing? What is the mutation rate like? Are these patient-specific or can donor cells be used in many people without an immune system reaction? If patient specific, what are the issues with informed consent in drawing cells from a person with a neural disorder who does not understand the issue?

If the cells can differentiate into anything and can start beating in a lab dish, could they grow to be a human if implanted in a womb? I assume not, but I am not sure that the question of what is human is really resolved by this study (if the results are reproducible in humans). Is a beating heart cell derived from human sperm-producing cells not human life because it cannot be a whole organism? A step forward in technology and science will probably change the nature of the debate but not eliminate it.

I suppose I sound somewhat pessimistic. I am not in the sense that I think this is really exciting and promising research. But I retain my usual caution about getting hopes up on something that had not been demonstrated in people, and I think ethics is a constantly evolving field and new issues will emerge even as others are resolved.